1. Field of the Invention
The present invention relates to blood serum and dermally-derived cells for use in tissue repair. Particularly it relates to blood serum and collagen producing cells for use in the treatment of connective tissue injuries. Preferably the cells and the blood serum are autologous and the connective tissue to be repaired is a tendon or ligament. Also provided is a method of treating connective tissue injuries by the administration of blood serum and collagen producing cells directly to the site of injury. It also relates to the use of blood serum and muscle-like cells for use in the treatment of muscle injury, particularly skeletal muscle injury.
2. Description of Related Art
Injuries to connective tissue such as tendons or ligaments are known to take a very long time to heal, as long as several months or even years. In many cases, injuries to connective tissue such as the Achilles tendon or “tennis elbow” may never heal properly, necessitating surgical intervention. However, the tendon or ligament will never be the same as before injury since scar tissue will be present whether the injury is treated by non-surgical or surgical methods.
Normal tendons or ligaments are composed of arrays of collagen fibres (type I and type II) that are closely packed together. Collagen producing cells within the tendons, called tenocytes, produce the collagen molecules. Tendons are a mechanism by which muscles connect to bones which provide some elastic properties to modular forces, acting as springs in storing and releasing energy.
Ligaments attach bone to bone and also play a significant role in biomechanics. Both ligaments and tendons represent an orthopaedic challenge when damaged so it is very difficult, if not impossible, to restore the normal mechanical function of these tissues.
Treatment of tendon injury is rarely completely successful. Home treatment including rest, ice and over the counter pain relief such as ibuprofen may be sufficient. However, for more severe injuries, current treatments for tendonitis include strengthening exercises, soft tissue therapies, and physical therapy modalities. People with tendonitis and tendinosis may also benefit from a program of specific exercise designed to strengthen the force-absorbing capability of the muscle-tendon unit. Soft tissue therapies, like myofascial release, combined with new technology, such as the Theralase Cold Laser, has shown good success in treating these injuries.
Corticosteroid injections or topical applications may be used. Sometimes a doctor may inject a corticosteroid medication around a tendon to relieve tendonitis. Injections of cortisone reduce inflammation and can help ease pain temporarily. However, there are potential side effects. For example, repeated injections may weaken a tendon, increasing the risk of rupturing the tendon. Also, corticosteroid medications should never be directly injected into the tendon itself because this can contribute to tendon rupture. As an alternative to an injection, a corticosteroid solution can be topically applied to the painful region and drawn in through the skin using a gentle electric current via iontophoresis.
Another treatment method is dry needling. Dry needling is sometimes known as Western Acupuncture. The technique uses acupuncture needles inserted into specific trigger points that are commonly associated with acute and chronic musculoskeletal pain. Despite using acupuncture needles and some points that coincide with traditional Chinese acupuncture points, dry needling and Western acupuncture does not use any of the diagnostic or treatment philosophy associated with this system of healing. Dry needling is a discrete treatment system normally used as an adjunctive method of pain management of other therapies such as osteopathy. The therapeutic effect may be attributable to the induction of bleeding in the tendon.
The use of autologous blood injection is known to help with connective tissue injury. Direct injection of the patient's (autologous) blood into the tendon has been reported. Blood is drawn from the patient and centrifuged to increase the concentration of platelets. It is this fraction which is re-injected. The growth factors present in the blood promote healing in tendons, ligament and muscles. The injection site is identified and the needle guided by ultrasound imaging. Dry needling often accompanies the blood injection technique.
Disadvantages associated with these methods include scarring at the site of the tear or microtear, introduction of unwanted amounts of steroids into the system of the patient. Cell culture techniques have been used to generate tissue for repairing injured tissue in a patient. Cell culture techniques are various and widely described in the literature. In vitro studies utilise, in the main, monolayer culture techniques. Whilst these two-dimensional approaches offer a useful research tool, the lack of intact, in vivo characteristics and interactions limits their use. In order to generate tissue with structural integrity, numerous technologies have been developed which promote cell-cell and cell-matrix interaction to promote the creation of a three-dimensional structure for study or implant (WO03041568, WO04060426, WO06138552, WO08003320).
These techniques utilise mesenchymal stem cells (MSC)—often derived from bone marrow (U.S. Pat. No. 5,197,985), tenocytes and fibroblasts. MSC are favoured in cell therapy protocols because of their ability to differentiate into many other different types of cells including cartilage, bone, muscle, tendon, fibroblast and adipocyte (WO2004022078). Embryonic stem cells (ESC) are also used to create functional tissue grafts. As such, these techniques are primarily targeted at relatively large scale or acute tissue tears, to re-approximate two broken ends or for total tissue replacement.
Other types of cells have been used in cell therapy, including fibroblasts, osteoblasts and chrondrocytes. To date, fibroblasts have been used as a component in a combinational closure for skin defects (WO02078721), as a cosmetic tool for aesthetics (DE69330129) and as a seed for synthetic and/or biodegradable matrices to generate three dimensional structures, pre-implantation and in vivo (U.S. Pat. No. 6,123,727, U.S. Pat. No. 6,140,039, U.S. Pat. No. 6,840,962, US2005060033, WO03043486, WO2001032129, CN1507926). Fibroblasts and fibroblast growth factor have been isolated from dermal tissue (WO03078607) and bone (WO05007811).
The implantation of cultured cells into a patient's tissue has the additional challenges of helping the implanted cells adapt to their new situation. Even when autologous cells from the patient's own body are used, the cells must still be integrated into the new site and use, or develop, means for receiving oxygen, sources of nutrition, and means for maintaining metabolic activity, amongst other adaptable functions. Cell culture techniques, treatable defects, factors that improve the successful adaptation of living cells to an implant site have also been described (WO08808229).
These embodiments of cell therapy include treating a defect in a patient with in vitro expanded cells and implanting into the tissue defect the cells with a helpful protein or other factor (e.g. proteins, macromolecules, molecules). Examples of such factors include immunogenic proteins, cell adhesion mediating proteins, apoptosis inhibitors (WO07035843), anoikis inhibitors (WO7035843), protease inhibitors, gene of interest, signal transduction proteins, anti-scarring agents (WO5051232), differentiation factors, vasodilators, angiogenesis proteins, pro-inflammatory proteins, pro-coagulation proteins, promoters of extracellular matrix (ECM) production (WO08070893), transport proteins, survival factors, a serum protein, cell culture serum-derived proteins and factors (WO9960951), chemoattractants (WO07022188), an ECM protein produced from culture (EP1263931), growth factor (WO03059932), cytokins (WO08086147), chemokines (WO05014026), hormones, space filling proteins and factors, soluble proteins, insoluble proteins, recombinant proteins, domains and fragments of proteins, peptides (WO0049136), gellable factors (WO0387303), amongst others that are apparent throughout the text and in the art. Depending on the application, other proteins and factors can be used that promote survival of the cells and optimize cell functionality.
More recently, and specific to the field of repair of chronic tendon tear in humans, studies utilizing autologous blood injection, proximal to and directly into the trauma site have demonstrated improved tissue repair characteristics. Treatments already known in this field includes the method of repairing tissue by the co-administration of blood components with a polymer which, on mixing turns into a non-liquid state to retain and adhere the therapeutic agents to the site of repair (US20020082220, US005709854, WO8064487) and the introduction of platelet-rich plasma (US6811777, WO08022651).
However there still remains a need for a reliable and effective method of tissue repair without the generation of scar tissue that provide reliable results in the healing of the tissue in a rapid efficient way with minimal disruption to the patient. There is a particular need for a treatment for connective tissue injury and muscle injury.